In person where and when? These are not the easiest signatures to just get on the street, especially Brady and Belichick. The odds of this being authentic are pretty low.
The story should concern you if you're looking to make a purchase, especially when it concerns the Michael Jordan of football. If someone is selling a signed football along with a story, I'd want the details - and proof of some sort. Saying "got it at training camp" is not plausible, given Brady's stature, elusiveness and what people are currently paying for private signing signatures. I've seen plenty of Aaron Rodgers "autographs" allegedly signed at training camp, and the story is every bit as laughable as the signature. Also, you might want to ask how he went to training camp and only ended up with signatures of the biggest names on the team. When I see items that are actually signed at training camp, more often than not it's a combination - maybe a couple stars, a lot of role players and backups and usually more than a few people who get cut.
the Brady does not scream out "forgery". the stye is fairly consistent with his. but there are also a lot of forgeries out there, so no way to be certain.